Regulator for alternating-cu rrent dynamos



(No Mom. 2 Sheets-Sheet 1..

E. W. RICE; Jr. REGULATOR FOR ALTERNATING CURRENT DYNAMOS. No. 546,190.Patented Sept. 10, 1895. 3191 E a v If g Q 7 T m 1 f 2 Ill/E111 Ur.-

mmwu g ANDREW B.GRAHAM. PHUTOLITNUWASIUN GTON. DC.

(No Model.) 1 2 Sheets-Sheet 2. .E. W. RICE, Jr. REGULATOR FORALTERNATING CURRENT DYNAMOS.

No. 546,190. Patented Sept. 10,1895.

Irg'rinr:

mam

Ming/2E5:

@wa/r i 9 ANDREW B.GRAIHAM. PHOTO-LH'NQWASHINGTON. [7.0.

UNrran States PATENT rates,

EDWIN \VILBUR RICE, JR, OF LYNN, MASSACHUSETTS, ASSIGNOR TO THETHOMSON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

- produced byavarying current flowing through REGULATOR FORALTEFlNA'T'lNG-CURRENT DYNAMOS.

SPECIFICATION forming part of Letters Patent No. 546,190, datedSeptember 10,1895. i

I Application filed March 16, 1838. Serial No. 267,352. (No modeld ToaZZ whom, it may concern.-

Be it known that I, EDWIN 'WILBUR RIoE, Jr., a citizen of the UnitedStates, and a resident of Lynn, in the county of Essex and State ofMassachusetts, have invented a certain new and usefulAlternating-Current Dynamo, of which the following is a specification.

My invention relates to alternating-current dyn'amos designed topreserve a constant difference of potential or a certain predeterminedincrease or diminution of potential, according as the conditions mayrequire.

It consists, chiefly, in a novel means of varying the magnetic field, soas to increase or diminish its action on the armature in such manner asto compensate for the losses due to resistance and distortion of thelines of force the armature-conductors.

My invention consists in charging the fieldmagnet from two independentsources, one of which is a practically constant source and consistseither of permanent magnetism, electricity from a separate dynamo, or ofcurrent from a coil upon the armature or armature-shaft of the alternatiug dynamo itself, while the other is a variable charging force andconsists of the main-line current or a portion of the mainline currentwhich passes to the alternatingcurrent main supplying the work, suchcurrent being at a point on the circuit locally commuted by means of acommutator to two opposite terminals of which the two terminals of afield-exciting coil are respectively connected. By this means thecurrent forming the latter source is made to vary with the external workand can therefore be made to increase the power of the field-magnetsexactly as the demands upon the machine increase. In connection with thecommutator and the variable-current coil, both of which are placed inthe main circuit leading to an alternating main, I employ a branch forsaid circuit around the coil, which branch includes a resistance havingcomparatively no self-induction and made preferably .variable,as will bemore fully hereinafter described. By this means sparking at thecommutator is prevented when a change of load occurs on the externalcircuit, as will be more fully hereinafter set forth.

My invention consists, further, in the particular combination ofapparatus which will be more precisely stated in the claims.

The advantages of my invention are simplicity, certainty of action,freedom from sparking at the commutator, and automatic compensation forvarying load.

It has heretofore been proposed to obtain automatic compensation for analternating dynamo, but in the apparatus before employed the commutatorwhich supplies the variable field-circuit has either been in thesecondary circuit from a transformer or induction-coil or has beenplaced in a derived circuit from the work. These methods are more orless complicated and not so satisfactory, and are moreover liable tocause trouble by sparking at the commutator. In my invention thevariable field-magnet coil is in direct circuit with the work suppliedwith alternating currents.

Referring to the drawings, Figure l is a perspective view of analternating dynamo and separate exciter as combined in accordance withmyinvention. Fig.2 is a diagrammatic view of the connections oftheapparatus illustrated in Fig.1. Fig. 3 is a diagrammatic view of amodification of my invention, where the exciting-dynamo is dispensedwith and the constant exciting-current is furnished by a conductor woundupon the armature of the alternating dynamo itself and commuted by acommutator. Fig. 4c shows in detail the method of winding the separateconductor used in furnishing the constant or initial current. Fig. 5shows my invention applied to two dynamos in which the initial orconstant current for exciting the fields is furnished by a separatedynamo and in which the variable field is produced by commuting the maincurrent furnished by each dynamo.

Referring to Fig. 1, A indicates the armature of an alternating-currentdynamo of any desired construction, the coils l, 2, 3, 4, &c., for thesame being shown in the present instance as wound upon the exterior ofsuch armature. The armature A may be constructed of anumber of thin ironplates carried by and secured to the shaft in any wellknown manner. F isthe main field-winding, connected through the rhoostat R to the positiveand negative brushes of the exciter E. F is the accessory field-winding,wound preferably as shown 011 each field-pole and on that portion of thepole-piece nearest the armature-conductors. One or two of thefieldmagnets may be wound with the variable field F, the remaining onesbeing supplied only with the constant current. The field-winding F hasits two terminals connected respectively to two terminals of acommutator, the cylinder of which is indicated at K, while the brushestherefor are indicated at B B. The commutator-cylinder K is madeup, asusual in the art, of one or more pairs of com mutatonplates insulatedfrom one another. The field-winding F is in the present instance shownas connected to the two terminals of the commutator, consisting of thebrushes B B. The two other terminals of the commutator, consisting ofthe two sets of segments, are connected,as will be seen, respectively toone pole or terminal of the armature-coils and to the exteriorcircuitthrough the ring 0. The commutatorcylinder is fastened to theshaft and provided with a number of segments equal'to the number ofalternations of current during a revolution of the armature. Thiscommutator K may be constructed in any well-known manner, alternatesegments being connected together so as to make practically a two-partcommutator. In constructing and operating this commutator it isobviously only necessary that the changes of connection thereon shouldbe timed to occur simultaneously with the alternations of the currentsupplied from the armature'coil to the main and the work. 0- O are twocollecting-rings, upon which bear two brushes D D connected,respectively, to the terminals of the working circuit T T.

The electrical connections of the apparatus are more clearly shown inFig. 2, in which similar parts are referred to by corresponding lettersand numerals.

Fig. 2 shows diagrammatically the connections used in the alternatingdynamo and the eXciter, Fig. 1. The field-winding F is furnished with aconstant current from the ex citer E, which current flows from thebrush 1) of the machine E through the resistance It, through thefield-coils F, back to brush 1). The current from the exciting-dynamo Ealso divides through the brush Z), through the resistance R and its ownfield S to brush b. The current flowing through the field F cantherefore be regulated either by varying the resistance R which variesthe field S, thereby acting on the armature a, which generates thecurrent flowing through the circuit between the terminals 1) b, or thecurrent through F may be varied directly by varying the rheostat R. Incases where a single alternating dynamo is used the rheostat R would bedispensed with and the current flowing through the field F controlledentirely by means of the resistance B A, Fig. 2, indicatesdiagrammatically the armature-conductor, one terminal of which isconnected to the segon the ring 0, and from D a wire is led to theexternal circuit containing the translating devices T T, &c., from whichtranslating devices the current runs back to the brush 1),collecting-ring C, and from collecting-ring U to the armaturc-conduct rA, thus completing the circuit. The field F is connected between theterminals of the brushes 15 I3 which are bearing upon the commutator It.The effect of these connections'is, as will be seen, to put one terminalof the armature-coil A directly in circuit with one of the mains throughthe ring 0 and brush D, so that the alternations of current from saidcoil may pass directly to the main and to the work without beingcorrected. The circuit from the other terminal of the armature-coil tothe opposite main is, briefly speaking, through the commutator and thefield-exciting coil F to the other main, the coil being included in thecommutator connections, so that the alternations of current will belocally commuted therein.

The resistance R with no or com 'iaratively little self-induction, isconnected between brushes B B, thus forming a branch for the maincurrent around the coil F.

The method of operation is as follows: When the armaturecondnctorArevolves within the influence of the field F, the current through whichis constant in amount, being furnished by the exciter E, as justdescribed, the electromotive force produced between the terminals ofarmature-conductor A has a certain fixed value. The amount can bealtered by varying the current through F. No current flows through thefield F or the commutator K or collecting-rings O C until the circuit isclosed through the external devices T T, the; but when so closed thecurrent flows through the armature A, one set of com mutator-blocks forthe commutator-cylinder K, brush ll, coil F, brush B, to the otherset ofcom m utator-blocks or plates, collecting-ring 0, brush D, translatingdevices T, to brush D, collecting-ring 0, back to the armature-conductorA. The field-winding F, being in the comm utingconneetion between theterminals 13 B of the commutator, receives currents which are continuousor always of the same direction, but which on other portions of the maincircuit alternate in the usual way. The amount of current thus tlowinginthe continuousctnrent coil F is obviously dependent upon the amountdemanded by the translating devices T T, (he. Acertain portion of thecurrent is diverted by the resistance R for the purpose of regulatingthe field F. As ordinarily constructed an alternating dynamo would nothave the commutator K nor auxiliary field F. In this case when theexternal translating devices T T were thrown into action the cur rentflowing in the armatureconductor A wo'ulddistort the lines of forcepassing into the armature, and the potential between the terminals of Awould therefore fall in amount. It would also fall in consequence of theresistance offered by the armature-conductor A. It would then benecessary to increase the amount of current passing through the field Fin any well-known manner-such as varying the resistance R R as is wellknown in the art. This, however, requires the manipulation of aresistance and constant attendance in order to prevent fluctuations inpotential between the terminals of the translating devices inconsequence of the varying amount of work demanded of the dynamo. Byinserting the commutator K and commuting the main current and sending itthrough the auxiliary field F, I am enabled to increase the fieldautomaticallyin exact proportion to the amount required to keep thepotential up to the proper amount. By properly proportioning the numberof turns of the field-wind ing F the fall of potential due to the causesmentioned abovei. e., the armature resistance and the distortion of thelines of force can be entirely compensated for-that is, the potentialcan be made to remain constant in amount upon throwing on the externaltranslating devices. It is frequently found desirable in long circuitsto save copper wire, a certain amount of loss being introduced betweenthe dynamo and the translating devices T T. The fall of potential with agiven res to make the necessary compensation.

sistance depends upon the current flowing through the circuit, andtherefore in order to keep the potential constant at the translatingdevices T T it is necessary that the potential at the terminals ofthedynamo should be increased. This can be accomplished by a properproportioning of the field F. To facilitate this proportioning I haveplaced as a shunt about the field F the variable resistance R By varyingthe amount of the resistance R I am enabled to divert a portion of themain current from the field F, and thereby adjust it so as to produceany desired effect. In order to accomplish this the field F must bewound with Wire fine enough so that the field produced by it, in casethe whole current is passed through it, is more than is desired In thiscase the resistance R is adjusted to divert just such proportion of thecurrent as may be desired. 1 have also found that the resistance R has anew and even more valuable use than that referred to above. I find inpractice that if the resistance R is omitted and the current in theexternal circuit is changed suddenly the commutator K sparks badly for afew moments and then gradually ceases sparking. This is objectionable,as it is liable to produce fluctuations in the lights or-other externalwork and burns the commutator and its brushes. The sparking is caused bythe fact that the field-winding F has a large selfinduction and will notallow a sudden increase or diminution of current to occur in itswinding, in consequence of which the current passes across the slots ofthe commutator K, causing the sparking mentioned, until such time as thefield F has time to take up the line-current or to lose the currentwhich is passing through it, when the sparking ceases until anotherchange in the current takes place. By placing the resistance R which haslittle or no self-induction, in parallel arc with. the field-winding F,I am enabled to entirely obviate this sparking, the resistance R forminga path for the current in case it increases and also a path for thedischarge of thecurrent in F when the main-linecurrent diminishes. Thisallows the main-line current to increase or diminish suddenly withoutaffecting the commutator K. Of course it is understood that theresistance R takes up this-current only during the time in which thevariation in current is taking place, and that as soon as the currentceases to vary the constant current flowing is divided between F and Rin proportion to their actual resistance.

Referring to Fig. 3,in which similar letters and numerals refer to thesame parts as in Figs. 1 and 2, and the same parts have similarfunctions, the constant field F, instead of being supplied by anotherdynamo or separate source of current, is supplied by a current generatedin a conductor wound upon the armature of the alternating dynamo itself.This conductor a may be Wound over the surface of the armature, as shownin detail in Fig. 4, and instead of being wound in the form of a coil onthe exterior of the armature, as are the coils 1, 2, 8, 4:, &c., it iswound transversely, as is shown clearly in Fig. 4. Thearmature-conductor 0, is carried out to a commutator N, which isconstructed with as many segments as there are alternations during arevolution of the armature. The commutator N is the same in constructionas the commutator K and commutes the alternatingcurrents produced in thearmature-conductor a into a continuous current, which supplies thefield-winding F. This armature-conductor, being independent of thearmature-conductor A, furnishes a current very nearly constant inamount. Inpractice the current flowing through the armature conductor a,and therefore the field F, diminishes slightly with an increased currentflowing through the main armature-conductor A. .It is thereforedesirable in this case that the variable field F should be soproportioned as to increase slightly more in effect than it would incase the field F were furnished by an external source.v This proportioncan readily be found by varying the resistance R until the potentialbetween the terminals of the armature-conductor or collecting-rings C Cre mains constant or increases in any predetermined ratio.

Fig. 4 shows in detail the method of winding main coils onarmature-conductor A and the exciting-conductor a. Fig. 5 showsdiagrammatically my invention applied to two dynarnos, in which thefield-coils F F are sup plied by the same exciter E. The numerals andletters have the same significance as in the preceding figures. Theexternal circuit T T T T can be separate circuits, as shown, or they canbe connected in multiple arc in case the two dynamos are run together.In this case the resistance R R can be so adjusted as to give the properinitial field for the armature-conductors A A, and the resistance R canbe so adjusted as to cause such an excitation of the field-coils F I aswill give a uniform potential between the collecting-rings O O or anincrease of potential, as may be predetermined upon, as described above.The Whole system may then be governed by the resistance R in the fieldof the exciter E.

What I claim as my invention is 1. The combination in an alternatingcurrent dynamo, of two field sustaining coils, one supplied from anarmature coil connected directly therewith through a commutator, and theother forming a path for the main alternating currents passing to thework from an independent armature coil or coils, a commutator placed inthe main circuit for locally commuting currents to said latter coil, abranch from the commutator terminals which are connected to said coil,and an artificial resistance in said branch.

2. In an alternating dynamo electric machine, the combination of acontinuous current field exciting coil placed in the circuit to thealternating current work, and provided with a rectifying commutator forlocally commuting the Work current in said coil, a variable resistancebranch around said coil in a commuted portion of the circuit and of lowself-induction, in combination with a field magnet coil through which acurrent flows of a strength independent of variations in the Work, asand for the purpose described.

3. The combination in an alternating current machine, of a field magnetproduced by two independent sources, one practically constant and theother variable, of a branch having practically no se1f-induction aroundthe coil forming the variable source, and means for Varying theresistance in said branch.

4. In an alternating current machine, the combination of a commutator,an armature coil one pole of which connects directly with the Work so asto supply alternating currents thereto while the otherpole connects withthe opposite main through the commutator, and a field magnet coil inwhich the varying main line currents are locally straightened by meansof said commutator, in combination with a variable resistance in abranch across the terminals of said field coil between the same and thecommutator, and a field sustaining coil in which a practically constantcurrent flows, as and for the purpose described.

5. In an alternating generator the combination with the field magnetcoilandcommtr tator placed in the alternating current main, of a brancharound said coil taken from a commuted portion of the circuit, and afield sustaining coil of practically constant elfect, as and for thepurpose described.

6. In an alternating generator he combination with the field sustainingcoil of practically constant effect, and a field magnet coil andcommutator therefor placed in the alternating current main, of avariable resistance placed in a branch of the main around said coil andconnected to the circuit at points between the coil and commutator, asand for the purpose described.

7. In an alternating generator, the combination with the field magnetcoil and the pole changing commutator therefor placed in the alternatingcurrent main, of a branch of the main from the commutator around saidcoil, and a field sustaining coil of practically con stant effect, asand forthe purpose described.

8. In an alternating generator, the combination with a field sustainingcoil of practically constant elfect and a field magnet coil and polechanging commutator therefor placed in the alternating current main, ofa variable resistance in a branch of the main around said coil, as andfor the purpose de scribed.

Signed at Lynn, in the county of Essex and State of Massachusetts, this12th day of March, A. D. 1888.

' E. WILBUR RICE, JR. \Vitnesses:

J. W. Grnnonnr, GEO. F. CURTISS.

